Making oxalic acid from cane sugar

oxalic acid is commonly used to bleach wood or remove rust and it's also used by some beekeepers to fight against parasites it's not super toxic but it is dangerous if ingested oxalic acid is the reason why it's bad to drink antifreeze or for example eat rhubarb leaves rhubarb leaves themselves contain a lot of oxalic acid and antifreeze which is also known as ethylene glycol is broken down into oxalic acid in your body when the oxalic acid gets to your kidneys it turns into the salt form of oxalic acid called calcium oxalate and this precipitates out and can form a solid blockage if enough calcium oxalate precipitates it can actually lead to kidney failure in terms of chemistry oxalic acid is the simplest dicarboxylic acid and it's relatively strong considering it is an organic acid I plan to use it to make something called oxalochloride which will in turn be used to make something called tcpo which is the chemical that's used in glow sticks the method that we use in this video to make the oxalic acid is by the oxidation of sugar and it's not the most efficient method and it's really not cost effective oxalic acid is really cheap and easy for most people to get so this method is more just for fun for this preparation I used about 50 grams of sucrose which is effectively just table sugar and about 250 milliliters of concentrated nitric acid the method that I'm using here is just a scaled up version of the one that's used by chemplayer and I'll provide a link to their video in the description I start off by adding about 50 grams of sugar to a 1 liter Beaker that already has a stir bar in it directly to the sugar I then pour in about 250 milliliters of concentrated nitric acid I then turn on the stir plate and I let things mix until all of the sugar has fully dissolved it takes a few minutes and we're eventually left with a perfectly clear solution and at this point I turn on the heating as we continue to heat things the solution will take on a very slight yellow color due to the presence of nitrogen dioxide as the solution gets hotter more nitrogen dioxide will be produced and the solution will slowly change from a yellow to an orange and eventually to a very dark red color shortly before the reaction really gets going the solution will take on a very slight red color then quite suddenly the solution will start to produce a lot of nitrogen dioxide gas and at this point we should turn off the heating we initially needed to heat things up to provide the activation energy for the reaction and to get things going however when things have started we can turn off the hot plate because the reaction between the nitric acid and the sugar releases its own heat and this is enough to sustain the reaction if we were to leave the hot plate on then the reaction might even go more out of control than it already is anyway as it's pretty obvious to see this reaction produces a lot of dangerous nitrogen dioxide gas so for this reason this experiment must absolutely be done in a very well ventilated area the overall reaction is shown here where nitric acid oxidizes sucrose to oxalic acid sucrose here looks large and complicated and this is because it's a disaccharide which means that it's a sugar consisting of two smaller sugar units the two smaller units of sucrose are glucose and fructose and they're connected together by an acetal Bond under the acidic conditions that we have here the acetal bond is easily hydrolyzed and we Liberate the fructose and glucose monomers initially the glucose is mostly oxidized by nitric acid to something called sicaric acid and fructose is oxidized to two keto d-gluconic acid or some other oxidized fructose derivative these already oxidized sugars are then oxidized even further which breaks some carbon-carbon bonds and we ideally form oxalic acid and some four carbon side product in general this process is really messy and although oxalic acid is the major product it also produces a slew of side products after around 10 to 20 minutes the reaction should have died down and at this point we begin to heat things again the goal now is to boil down the solution to about 75 milliliters it's really not important to get it down specifically to 75 milliliters and I think anything between 60 and 90 is probably good anyway I eventually get down to around the 75 milliliter Mark and then I pour in an equal amount of distilled water then with this new fresh water added we boil everything down to about 50 milliliters once we hit around the 50 milliliter Mark the heating is turned off and the solution is allowed to cool to room temperature as the solution cools it will eventually solidify as oxalic acid starts to precipitate out the oxalic acid here still looks a little bit yellow due to the presence of nitrogen dioxide but that'll eventually go away the oxalic acid was placed in a freezer to fully precipitate everything and you can see at this point that it's no longer yellow the next step is to filter off the oxalic acid and when I go to remove it from the beaker you can see it's kind of a gooey mess anyway after a little bit of trouble I managed to get all of the gooey oxalic acid into a vacuum filter to clean things up a little the oxalic acid is washed a few times with ice cold water each time the water is added everything is mixed thoroughly to make sure that it gets a good washing this washing step is repeated a few times and at the end we're left with very nice white and clean oxalic acid although washing with water does clean it up we probably lose a significant amount because oxalic acid is actually quite soluble in water anyway once we're done with the washing steps I pull a vacuum on it for a few minutes just to try to get rid of as much water as possible the oxalic acid then scraped out of the filter funnel and onto a piece of paper to dry by leaving it out for something like a day in open air it actually dries up pretty nicely in the end the yield was about 16 grams of oxalic acid dihydrate which is actually quite low I don't think this reaction is super efficient on its own and those added washing steps that I used really didn't help either in the end though the best way to get oxalic acid is just to buy it because this method does use a lot of valuable nitric acid I really only recommend doing this method if you have no other way to get oxalic acid anyway as I said before this oxalic acid is eventually going to be used to make exalt chloride and then tcpo right now I'm just waiting on some glassware in the mail which I'm going to use to convert red phosphorus to white phosphorus which is needed to make the auxil chloride anyway as usual that's all I have to say for now and I'll see you guys on the next one again I'd like to extend a big thanks to everyone who supports me on patreon all of my videos are shared 24 hours before with all of my patreon supporters before I post it to YouTube and everyone who supports five dollars or more per video actually gets their name at the end as you see here I would also like to reiterate that I only charge patrons for the long in-depth videos and none of the short ones are ever charged to anyone everyone gets those for free anyway that's it for now I'm not a hundred percent sure what the next video is but it should probably be posted later this week

Channel: NileRed

Views: 259,706

Keywords: nile, red, how, to, anhydrous, oxalic, acid, cane, sugar, sucrose, oxidation, nitric, chemistry, science, nilered, nileblue

Id: M5bAbvw6IQQ

Length: 7min 54sec (474 seconds)

Published: Wed Jun 08 2016